In resource poor regions of the world where HIV is endemic, especially countries in sub-Saharan Africa, nutrition plays a critical role in HIV disease. Nutrition affects the health of HIV-infected women and children, and may influence the risk of mother to infant transmission of HIV through breast milk. Nutrition influences the risk of tuberculosis (TB) and TB disease severity. Existing research has focused on the role of micronutrients in HIV disease outcomes but has not addressed the role of protein calorie supplementation (PCS) in subpopulations of patients with HIV disease at high risk, specifically;HIV-infected women who are either breast feeding or have active TB. Our hypotheses are that administration of a culturally acceptable PCS is a practical, sustainable and effective strategy to: 1) decrease HIV viral load in plasma and breast milk of breast feeding women, enhance passively transferred immune mediators in breast milk, and improve HIV outcomes in women and their breast-fed infants and, 2) decrease HIV viral load, enhance TB-specific T cell immunity, and improve outcomes in women with HIV and active TB. Our two specific aims are to show that these strategies are effective in randomized clinical trials. Drawing on the 8 year DarDar collaboration between Dartmouth and Muhimbili University of Health and Allied Sciences in Tanzania we will conduct 3 nutritional studies among HIV-infected women in Dar es Salaam. Study A will enroll 160 HIV+ and HIV- women who are either breast feeding (BF) or have active TB to conduct dietary interviews and focus groups to quantitate existing nutritional deficiencies and to define a culturally acceptable PCS. Studies B (118 HIV+ and 60 HIV- women who are breastfeeding) and C (118 HIV+ and 60 HIV- women with active TB) are randomized controlled trials which will compare the effects of 6 months of PCS + micronutrient supplement (MNS) vs. MNS alone on overall disease outcomes as well as specific surrogate markers of HIV disease, specific immune factors in breast milk and specific T cell responses against TB. Findings from these studies are expected to have a major impact on policies for nutritionally vulnerable HIV subpopulations.